MCQ Detailed View

Laughing gas is a common name for a chemical compound called nitrous oxide (N₂O). It is a colorless, non-flammable gas with a slightly sweet smell and taste. The gas is often used in medicine and dentistry because of its anesthetic and pain-relieving properties. When inhaled, it can make a person feel light-headed and sometimes laugh uncontrollably, which is why it is called "laughing gas."

The chemical composition of laughing gas consists of two elements:

1. 
   

   Nitrogen (N) – a colorless, odorless gas that makes up about 78% of Earth’s atmosphere.

   
   


2. 
   

   Oxygen (O) – an essential gas for respiration and combustion.

   
   

In nitrous oxide, two nitrogen atoms combine with one oxygen atom, giving the molecular formula N₂O. The bond between these atoms makes the gas stable and safe for controlled use.

The other options are not correct:

• 
  

  Nitrogen + Hydrogen combine to form ammonia (NH₃), not laughing gas.

  
  


• 
  

  Nitrogen + Carbon form compounds like cyanides or carbon nitrides, unrelated to laughing gas.

  
  


• 
  

  Oxygen + Carbon form carbon dioxide (CO₂) or carbon monoxide (CO), different gases used in other processes.

  
  

Laughing gas works by depressing the nervous system, creating a calming and euphoric effect. It is often used in minor surgeries, dental treatments, and pain management because it acts quickly and wears off fast without leaving the patient unconscious.

In chemistry, understanding compounds like nitrous oxide helps explain how elements bond to form gases with specific properties. It also shows how a gas with simple elements can have important medical and industrial applications.

Therefore, laughing gas is made of Nitrogen and Oxygen, making Option 3 the correct answer.